i have a 99 ex coupe and i did the usual intake header exhaust a while back and also a high flow cat and was throwing like 9 codes! my car had a bad idle problem forever. NOw i have converted to OBD1 and i am throing only 1 code a 41 (02 sensor i think) but it still idles up and down when if first starts? Does anyone know what it could be?

 

exhaust or vacuum leak??

 

1.) Check to make sure the O2 is functioning
2.) Stop w/ the open polls

 

Well, if you're running OBD1 and have an O2 sensor malfunction that there's a problem with the primary sensor. Maybe it got damaged during your header install or whatever, or maybe it's not tight enough and is reading wrong.